Inclination Adjusting Device for Chair Seat

ABSTRACT

An inclination adjusting device includes an upper seat mounted below a chair seat of a chair. A coupling member is mounted to a rear end of the upper seat and includes a plurality of vertically spaced engaging portions. A lower seat is pivotably mounted to and below the upper seat. An inclination adjusting rod is pivotably mounted to a rod mounting board in the lower seat. An actuating board is connected to the inclination adjusting rod and includes at least one engaging protrusion for releasably and selectively engaging with the vertically spaced engaging portions of the coupling member. The inclination adjusting rod is pivotable between a first position in which the at least one engaging protrusion is engaged with one of the engaging portions of the coupling member and a second position in which the at least one engaging protrusion is disengaged from the engaging portions of the coupling member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an inclination adjusting device and, more particularly, to a device for adjusting an inclination angle of a seat of a chair.

2. Description of the Related Art

FIG. 8 shows an exploded perspective view of a conventional inclination adjusting device for a chair seat. FIG. 9 shows a partially-sectioned side view of a conventional chair 8′ with the inclination adjusting device of FIG. 8 that can adjust an inclination angle of a seat 68 of the chair 8′. The inclination adjusting device includes a swayable seat 1′ having fixing holes 11′ for coupling with the seat 6′. A coupling hole 12′ is defined in a central portion of the swaying seat 1′ for coupling with a spring device 3′. A coupling rod 5′ is extended through a through-hole 14′ in a sidewall of the swayable seat 1′ and through aligned through-holes 23′ in two lateral sidewalls of a coupling seat 2′ to allow pivotal movement of the swayable seat 1′ relative to the coupling seat 2′. A pneumatic rod 7′ is extended through a vertical receiving hole 21′ in the coupling seat 2′. The spring device 3′ is mounted in an opening 24′ of the coupler 2′ and includes a spring 31′, a sleeve 32′ for receiving the spring 31′, and a screw rod 33′ extending through the coupling hole 12′ of the swayable seat 1′ and coupled with a bottom end of the sleeve 32′. An adjusting rod 4′ is extended through a through-holes 13′ in one of two lateral sides of the swaying seat 1′ and through aligned through-holes 22′ in the lateral sidewalls of the coupling seat 2′. The adjustable rod 4′ includes a pressing portion 42′ adjacent to an engaging end 41′ thereof. When the engaging end 41′ is engaged in a through-hole 13′ in the other lateral sidewall of the swaying seat 1′, swaying motion of the swayable seat 1′ is prevented. The pressing portion 42′ presses against an end of the pressing rod 7′ to adjust a height of the seat 6′.

The resilience of the spring 31′ allows the backrest 8′ and the seat 6′ to simultaneously sway rearward, as shown in FIG. 10. However, since the swaying angle of the backrest 8′ is the same as that of the seat 6′, a user sitting in the seat 6′ is liable to fall backward due to excessive rearward inclination of the backrest 8′. Furthermore, the rearward inclination angle of the backrest 8′ can not be adjusted.

A need exists for a device for adjusting and fixing the inclination angle of the backrest of a chair while providing safety use.

SUMMARY OF THE INVENTION

An inclination adjusting device for a chair seat according to the preferred teachings of the present invention includes an upper seat adapted to be mounted below a seat of a chair. A coupling member is mounted to a rear end of the upper seat and includes a plurality of vertically spaced engaging portions. A lower seat is pivotably mounted to and below the upper seat. The lower seat has a bottom adapted to engage with a pneumatic rod for adjusting a height of the lower seat. The lower seat includes a compartment. A rod mounting board is mounted in an intermediate portion of the compartment. A height adjusting rod is pivotably mounted to a side of the rod mounting board. The height adjusting rod is pressable against the pneumatic rod. An inclination adjusting rod is pivotably mounted to another side of the rod mounting board. An actuating board is connected to the inclination adjusting rod and includes at least one engaging protrusion for releasably and selectively engaging with the plurality of vertically spaced engaging portions of the coupling member of the upper seat. A linking member includes a front end pivotably connected to a rear portion of the lower base. The linking member further includes an intermediate portion pivotably connected to the coupling member. The linking member is adapted to engage with a backrest support member.

The inclination adjusting rod is pivotable between a first position in which the at least one engaging protrusion of the actuating board is engaged with one of the plurality of vertically spaced engaging portions of the coupling member of the upper seat and a second position in which said at least one engaging protrusion of the actuating board is disengaged from the plurality of vertically spaced engaging portions of the coupling member of the upper seat.

Other objectives, advantages, and features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partial, sectional view of a chair utilizing an inclination adjusting device according to the preferred teachings of the present invention.

FIG. 2 shows a top view of the chair seen from arrow A of FIG. 1.

FIG. 2A shows a cross sectional view of the inclination adjusting device of FIG. 1 according to section line C-C of FIG. 2.

FIG. 3 shows an exploded perspective view of the inclination adjusting device of FIG. 1.

FIG. 4 shows a cross sectional view of the inclination adjusting device of FIG. 1 with the seat of the chair in a horizontal position.

FIG. 5 shows a top view of the chair seen from arrow B of FIG. 4.

FIG. 5A shows a cross sectional view of the inclination adjusting device of FIG. 1 according to section line C8-C8 of FIG. 5.

FIG. 6 shows a cross sectional view of the inclination adjusting device of FIG. 1 with the seat in an inclination angle.

FIG. 7 shows a cross sectional view of the inclination adjusting device of FIG. 1 with the seat in an inclination angle larger than that of FIG. 6.

FIG. 8 shows an exploded perspective view of a conventional inclination adjusting device for a chair seat.

FIG. 9 shows a partially-sectioned side view of a conventional chair with the inclination adjusting device of FIG. 8.

FIG. 10 shows a partially-sectioned side view of the chair of FIG. 9 depicting simultaneous movement of a backrest and a seat of the chair.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An inclination adjusting device according to the preferred teachings of the present invention is shown in FIGS. 1-7 and can be utilized with a chair. According to the preferred form shown, the chair includes a seat 4, a backrest 6, a backrest support 61, having an upper end to which the backrest 6 is fixed, and a pneumatic rod 5 for adjusting a height of the backrest 6.

According to the preferred form shown, the inclination adjusting device includes an upper seat 1 fixed to and below the seat 4 and having a recess 11 in an underside thereof. A substantially U-shaped coupling member 12 is mounted in a rear end of the recess 11 (FIG. 3) and includes a plurality of vertically spaced engaging portions 121 a, 121 b, and 121 c in the form of grooves. The coupling member 12 includes aligned elongated holes 122 in two arms thereof.

A lower seat 2 is pivotably mounted to and below the upper seat 1. A bottom of the lower seat 2 is engaged with a top end of the pneumatic rod 5 (FIG. 1) so that adjustment of the height of the seat 4 can be achieved by adjusting the vertical position of the pneumatic rod 5. A rod mounting board 22 is mounted in an intermediate portion of a compartment 21 defined in the lower seat 2. An inclination adjusting rod 24 is pivotably connected to a side of the rod mounting board 22. The inclination adjusting rod 24 includes a substantially rectangular push member 241 having a spring hook 242. A positioning block 243 is fixed to the rod mounting board 22 by fasteners engaged in engaging holes 221 of the rod mounting board 22. The positioning block 243 is made of slightly flexible material and includes first and second inclined abutting faces 2431 and 2432 on a bottom side thereof (FIG. 2A). The first and second inclined abutting faces 2431 and 2432 meet at a tip 2433. The inclination adjusting rod 24 bears against one of the abutting faces 2431 and 2432. A height adjusting rod 23 has an end pivotably connected to the other side of the rod mounting board 22. The end of the height adjusting rod 23 presses against the pneumatic rod 5.

A support 25 is mounted in a rear portion of the compartment 21 of the lower base 2 and substantially parallel to the bottom of the lower base 2. The support 25 has a notch 251 in an inner end thereof. Two blocks 26 are respectively mounted on two sides of the upper face of the support 25. A cover plate 27 is mounted on top of the blocks 26 and has a notch 271. A space is defined between the cover plate 27, the support 25, and the blocks 26 for slideably receiving a rear section of an actuating board 28 having a thickness slightly smaller than that of the blocks 26. Thus, the actuating board 28 is slideable back and forth between the cover plate 27 and the support 25. The actuating board 28 further includes two engaging protrusions 281 on a rear end thereof for selectively engaging with the engaging portions 121 a, 121 b, or 121 c of the coupling member 12. A compression spring 282 is mounted around a front section of the actuating board 28. Two ends of the compression spring 282 are respectively attached to the actuating board 28 and the inclination adjusting rod 24. A spring hook 283 in the form of a screw is fixed to an intermediate portion of the actuating board 28. An end of a tension spring 29 is attached to the spring hook 283, and the other end of the tension spring 29 is attached to the spring hook 242. A spring mechanism 291 is mounted between the upper seat 1 and the lower seat 2.

A linking member 3 has a front end pivotably connected to a rear portion of the lower base 2. An intermediate portion of the linking member 3 is pivotably connected to the elongated holes 122 of the coupling member 12. Furthermore, the linking member 3 is coupled with a lower end of the support member 61 for the backrest 6.

An inner corner of an intermediate portion of the L-shaped rod mounting board 22 in the compartment 21 is engaged with a portion of an outer periphery of a fixing disc 7 for fixing the pneumatic rod 5. The structural strength of the fixing disc 7 is, thus, enhanced.

When the inclination adjusting rod 24 is in a position shown in FIG. 2, the tension spring 29 is in tension, the compression spring 282 is not compressed, and the inclination adjusting rod 24 bears against the abutting face 2431 of the positioning block 243 (FIG. 2A). The inclination adjusting rod 24 can be pivoted forward and move across the tip 2433 to the other abutting face 2432 of the positioning block 243 (FIGS. 5 and 5A). It is noted that the inclination adjusting rod 24 is securely retained in either abutting face 2431, 2432 unless an operator moves the inclination adjusting rod 24.

When the inclination adjusting rod 24 is pivoted forward (see FIGS. 4 and 5), the push member 241 urges the actuating board 28 to pivot rearward. It is noted that the resilience of the tension spring 29 biases the inclination adjusting rod 24 to pivot forward whereas the actuating board 28 compress the compression spring 282. After moving the upper base 1 to a desired position, the engaging protrusions 281 of the actuating board 28 are engaged with the engaging portions 121 a, 121 b, or 121 c at the desired height under the returning force of the compression spring 282.

When the engaging protrusions 281 of the actuating board 28 are engaged with the engaging portions 121 a (FIG. 4), the upper face of the upper base 1 is substantially parallel to the ground. When the engaging protrusions 281 of the actuating board 28 are engaged with the engaging portions 121 b (FIG. 6), the upper face of the upper base 1 declines rearward in a small angle. When the engaging protrusions 281 of the actuating board 28 are engaged with the engaging portions 121 c (FIG. 7), the upper face of the upper base 1 declines rearward in a larger angle.

The two engaging protrusions 282 on two sides of the actuating board 28 engaged with the engaging portions 121 a, 121 b, or 121 c share the shear force acting on the actuating board 28 when the user is lying against the backrest 6. Enhanced support is provided, and breakage of the engaging protrusions 282 is prevented.

Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the preferred teachings of the invention. The scope of the invention is limited by the accompanying claims. 

1. An inclination adjusting device for a chair seat comprising: an upper seat adapted to be mounted below a seat of a chair, with a coupling member being mounted to a rear end of the upper seat and including a plurality of vertically spaced engaging portions; a lower seat pivotably mounted to and below the upper seat, with the lower seat having a bottom adapted to engage with a pneumatic rod for adjusting a height of the lower seat, with the lower seat including a compartment, with a rod mounting board being mounted in an intermediate portion of the compartment, with a height adjusting rod being pivotably mounted to a side of the rod mounting board, with the height adjusting rod being pressable against the pneumatic rod, with an inclination adjusting rod being pivotably mounted to another side of the rod mounting board, with an actuating board being connected to the inclination adjusting rod and including at least one engaging protrusion for releasably and selectively engaging with the plurality of vertically spaced engaging portions of the coupling member of the upper seat; and a linking member including a front end pivotably connected to a rear portion of the lower base, with the linking member further including an intermediate portion pivotably connected to the coupling member, with the linking member being adapted to engage with a backrest support member; with the inclination adjusting rod being pivotable between a first position in which said at least one engaging protrusion of the actuating board is engaged with one of the plurality of vertically spaced engaging portions of the coupling member of the upper seat and a second position in which said at least one engaging protrusion of the actuating board is disengaged from the plurality of vertically spaced engaging portions of the coupling member of the upper seat.
 2. The inclination adjusting device for a chair seat as claimed in claim 1, with the rod mounting board further including a positioning block fixed thereto, with the positioning block being made of a slightly resilient material and including two inclined abutting faces on a bottom side thereof, with the inclined abutting faces meeting at a top, with the inclination adjusting rod bearing against and being retained by one of the inclined abutting faces corresponding to one of the first and second positions.
 3. The inclination adjusting device for a chair seat as claimed in claim 1, further including, in combination: a tension spring having two ends respectively attached to the inclination adjusting rod and the actuating board, with the tension spring biasing the inclination adjusting rod toward the first position when the tension spring is in tension.
 4. The inclination adjusting device for a chair seat as claimed in claim 1, further including, in combination: a support mounted in a rear portion of the compartment and having an upper face, two blocks mounted on two sides of the upper face of the support, a cover plate mounted on top of the blocks, defining a space between the cover plate and the blocks for slideably receiving a rear section of the actuating board; and a compression spring mounted around a front section of the actuating board, with the compression spring having two ends respectively attached to the actuating board and the inclination adjusting rod, and with the compression spring being compressed when the actuating board is pivoted rearward, thereby biasing said at least one engaging protrusion of the actuating board to engage with one of the plurality of vertically spaced engaging portions of the coupling member of the upper seat.
 5. The inclination adjusting device for a chair seat as claimed in claim 1, with said at least one engaging protrusion including two engaging protrusions respectively on two sides of a rear end of the actuating board, with the engaging protrusions being adapted for sharing shear force acting on the actuating board when a user is lying against a backrest of the chair. 